Are human herpes viruses associated with autoimmune thyroid disease?

INTRODUCTION: Autoimmune diseases are complex diseases with genetic, endogenous and environmental etiologies. Viral infections have been postulated as one of the factors that may be the trigger of autoimmune diseases. METHODOLOGY: Thyroid peroxidase (TPO) and thyroglobulin (TG) antibodies were measured before thyroidectomy in 100 subjects by chemiluminescence method, 50 of whom were autoimmune thyroid diseases (AITD) patients and 50 of whom were multinodular goiter (MNG) patients used as a control group. Fresh thyroid samples were collected from all 100 subjects after thyroidectomy to investigate the DNAs of herpes simplex viruses types 1 and 2 (HSV-1, HSV-2), Varicella Zoster virus (VZV), Epstein-Barr virus (EBV), Cytomegalovirus (CMV) and human herpes virus type 6 (HHV-6) by PCR. RESULTS: The DNA of HSV-1, HSV-2, VZV, EBV, CMV and HHV-6 were detected in neither the patient group nor in the control group. The mean values of anti-TPO and anti-TG antibodies ranged within 9.5-2000 units/ml (527.8 ± 617.4) and 108-5000 units/ml (1458.2 ± 1774.1) in the AITD patients group, respectively. A statistically significant difference of the mean level of anti-TPO and anti-TG antibodies among the two groups was found (p value < 0.05). CONCLUSIONS: The possible role of human herpes viruses in the pathogenesis of AITD is not supported by our study; hence our raised question stays open for more investigation on more patients and in different parts of the country using different sizes and sites of biopsies.